Photographic materials

ABSTRACT

A PHOTOGRAPHIC GELATINO SILVER CHLOROBROMIDE EMULSION CONTAINING FROM 0.2 TO 3 GRAMS, PER GRAME MOLE OF SILVER IN THE EMULSION, OF A POLYETHYLENE OXIDE WHICH HAS TERMINAL END GROUPS SELECTED FROM THE CLASS CONSISTING OF HYDROGEN AND HALOGEN ATOMS, CARBOXYL, AMINO AND CARBAMOYL GROUPS, HIGHER FATTY ALCOHOL RESIDUES, SATURATED HIGHER FATTY ACID RESIDUES AND ALKYL PHENOL RESIDUES, AND FROM 0.5 TO 15 GRAMS OF WATER-SOLUBLE HYDROLYSED POLYVINYL ACETATE HAVING A MOLECULAR WEIGHT FROM 5000 TO 30,000 AND WHOSE RESIDUAL ACETATE CONTENT IS AT LEAST 35%.

United States Patent 3,666,475 PHOTOGRAPHIC MATERIALS David Ramsay Douglas, llford, England, assignor to Ilford Limited, Ilford, Essex, England No Drawing. Continuation-impart of application Ser. No. 575,518, Aug. 29, 1966. This application Apr. 28, 1970, Ser. No. 32,781 Claims priority, application Great Britain, Sept. 1, 1965, 37,360/65 Int. Cl. G03c 1/34, 1/04 U.S. Cl. 96-109 2 Claims ABSTRACT OF THE DISCLOSURE This application is a continuation-in-part of application No. 575,518, filed Aug. 29, 1966, now abandoned.

This invention relates to photographic light-sensitive materials, and more particularly to photographic materials intended for use in recording half-tone dot images or line images and which carry a gelatin silver halide emulsion of very high contrast characteristics, and which are designed to be developed in formaldehyde-containing lowsulphite hydroquinone developers as well as developers of the more usual types, and which exhibit in the former class of developers the phenomenon known as infectious development.

Emulsions of the foregoing type (which are herein referred to as lith emulsions) may be developed satisfactorily over a considerable range of development times, other development conditions being held constant. The effective speed of the lith emulsions increases as the development time is increased, and accordingly it is a valuable property of such materials that by controlling development time it is possible to control the eifective emulsion speed.

It is, however, desirable with such lith materials that the effective speed should not increase at too high a rate as development proceeds, e.g., during the first 2 to 3 minutes, since otherwise control of the image by inspection becomes very diificult.

It is, however, important in such lith materials that the contrast of the resulting images should remain high over as large a range of development times as possible and it is known to achieve this by the addition of polyethylene oxide compounds to the photographic emulsion so that normal formaldehyde/bisulphite/hydroquinone developer solutions can be used. However, the addition of polyethylene oxide compounds to lith emulsions has led to high fog on development.

It is the object of the present invention to provide a photographic lith type emulsion which comprises a polyethylene oxide compound which shows reduced fog on development.

According to the present invention there is provided a photographic gelatino silver chlorobromide emulsion consisting essentially of per gram mole of silver in the emulsion, from 0.02-3 g. of a polyethylene oxide which has terminal end groups selected from the class consisting of hydrogen and halogen atoms, carboxyl, amino, and carbamoyl groups and higher fatty alcohol residues, saturated higher fatty acid residues and alkyl phenol residues and from 0.5 to 15 g. of Water-soluble hydrolysed polyvinyl acetate having a molecular weight from 5,000 to 30,000 and whose residual acetate content is at least 35%.

The water solubility of the hydrolysed polyvinyl acetates depends on their residual acetate content, determined on a weight basis, and their viscosity characteristics (which in turn depends on their molecular weight). The hydrolysed polyvinyl acetates for use in the present invention must have a molecular weight of at most 30,000 (which means that they are of lower viscosity type) and should be so hydrolysed that they have a residual polyvinyl acetate content of at least 35%. Typical of such products is that commercially known as Gelvatol 40/10 referred to in Example I (Emulsion III) which has molecular weight 10,000 and residual acetate 40% and which is freely soluble in cold water.

It is preferred that the molecular weight of the polyethylene oxide or the polyethylene oxide modified by having at least terminal group substituted by a halogen atom or a carboxyl, amino or carbamoyl group should be between 1,000 and 15,000.

It is preferred that the molecular weight of the polyethylene oxide modified by having at least one fatty or alkyl phenol terminal group should be between and 15,000. Examples of higher alcohols which form ethers with polyethylene oxide are cetyl alcohol and oleyl alcohol. Examples of alkyl phenols which form ethers'with polyethylene oxide are isooctylphenol and nonylphenol. Examples of saturated higher fatty acids which form estedrs with polyethylene oxide are lauric acid and stearic aci The preferred chlorobromide emulsions for use in the present invention have a chloro-bromide ratio of from 1.5-15 chloride to 1 bromide.

The addition of either or both of the polyethylene oxide and of the water-soluble polyvinyl acetate can be made prior to or after the process of chemical sensitisation.

The following example will serve to illustrate the invention:

EXAMPLE I Emulsion I.A gelatin silver chlorobromide emulsion containing 31 mole percent of silver bromide, having a grain size of 0.2/L, was sulphur sensitized, stabilized and treated with an orthochromatic sensitizing dye. The emulsion was then coated on film.

Emulsion II.A similar emulsion was treated in the same manner except that 0.17 gr. polyethylene oxide (Carbowax 6000) was added prior to coating.

Emulsion 'III.An emulsion similar to that described above but with the addition of 0.85 gr. Gelvatol 40/ 10 per gram mole silver was prepared. Gelvatol 40/ 10 is a water-soluble polyvinyl acetate which is manufactured by Shawinigan Ltd., and has a molecular weight 10,000 and contains 40% residual acetate. Polyethylene oxide (Carbowax 6000) 0.03 gr. was also added prior to coat ing.

All coated emulsions were exposed behind an optical wedge in the usual manner. The exposed coatings were then developed in a developer made from the following solutions:

Solution A:

Sodium sulphitegr. Hydroquinone-45 'gr. 'Boric acid-15 gr. Potassium bromide-3.15 gr. Water to make 1,500 ml.

[For the incubation test samples of coated emulsion were Q Q i developed in a phenidone/hydroquinone based developer. Potalssmm me.mb1Su1ph1te5'25 The first column represents the fog level after 7 days nor- Sodmm sulph1tel.05 gr. 1 h H d th 6 1 Water to make 500 mL ma 5 e storage an e secon co umn represents the fog level after 7 days 1ncubation at 69% relative humidity The developer is made by mlxmg 3 parts of solution A at F with one part of solution B immediately before use.

[it will be seen from the results of the test coatings set EXAMPLE 11 out below that the use of polyethylene oxide and a watersoluble polyvinyl acetate in combination requires reduced The emu1S1n used was Emulslon of Example To t s emulsions was added the amounts of the polyethylene and line image quality is directly related to the higher conoxide compounds and the water-soluble polyvinyl acetmst achlevedtate shown in Table II, all the compounds were added to TABLE I 15 the emulsion prior to coating. lggge lgg Relative Cuntmst All the eoated emulsions were exposed behmd an op in minsJ log speed Incubation tog cal wedge 1D the usual manner. The exposed coatings were then developed in the same developer as used in Example I. The incubation test was carried out in a similar manner Solution B quantities of the polyethylene oxide. The improved dot Emulsion to Example I.

68977 mmwmw l It will be seen from the results set out below that the use of the polyethylene oxide compound and water-soluble polyvinyl acetate together requires reduced quantities of the polyethylene oxide to obtain the high contrast rem mm mmmm increase in incubation fog results.

TABLE II Gelvatol 4011;), Degelgl 1Belativg Contrast m m n e o s ee per silveii g in r inutes 1 g 810 (1) Incubation fog Description of polyethylene oxide I In tormaldehyde/hydroqulnone based developer.

Polyethylene oxide compound, per gram mole silver 0.04 0.05 Carbowax 6000. Unbranched poly ethylene oxide chain M.W..-. 6000.

0.05 gr. Garbowax 6000..--....---..-

Mmmmw 0.05 gr. Carbowax 6000.-.

0.04 0.06 Cetyl/oleyl ether on polyethylene oxidize) chain ethylene oxide um s 26220 5 &&7 7

19 moewoew LL2 2 2 0.165 Texofor A 60.

0.66 Texoior A 60..

0. 04 0.05 Alkyl phenol ether on polyethylene oxide (60 ethylene oxide units).

0.166 gr. Texofor F 60.

See footnotes at end of table.

TABLE IIContinued Gelvatol 40/10, Develop- Relative per gram mole merit time log speed Contrast silver, gr. in minutes 1 SLO Incubation tog Description of polyethylene oxide Polyethylene oxide compound, per gram mole silver 0.165 g. Texoi'or F 60 LLZ 2 2 0.165 g. Texoior F 60 wwo owm 2.14 Saturated fatty acid ester on polyeltrhiylene oxide (23 ethylene oxide 0.33 gr Texofor E 23.......-.....-.

9 1O wzues 2 22 2 2 1.33 gr. Texoior E 23 1 In formaldehyde/hydroquinone based developer.

I claim as my invention: 35 saturated higher fatty acid residues and alkyl phenol 1. A photographic gelatino silver chlorobromide emulresidues. sion having a chlorobromide ratio of from 15-15 chlorine References Cited UNITED STATES PATENTS 3,142,568 7/1964 Nottorf 96-87 3,052,544 9/1962 Dersch 96-107 3,158,484 11/1964 Willems et al. 96107 NORMAN G. TORCHIN, Primary Examiner 2. A photographic gelatino silver chlorobromide emul- 45 R. E. FICHTER, Assistant Examiner sion according to claim 1 wherein the polyethylene oxide condensation product has terminal end groups selected U.S. Cl. X.R.

to 1 bromine and consisting essentially of per gram mole of silver in the emulsion from 0.02-3 g. of a polyethylene oxide or polyethylene oxide condensation product as a 40 sensitizer having a molecular weight of 1,000 to 15,000 and from 0.5 to 15 g. of water-soluble hydrolized polyvinyl acetate having a molecular weight from 5,000 to 30,000 and whose residual acetate content is at least 35%.

from the class consisting of halogen atoms, carboxyl, amino, carbamoyl group and higher fatty acid residues, 

